In a three-node relay network where all channels experience quasi-static Rayleigh fading and where the instantaneous channel state information is not available at the transmitters, a situation can occur where the network does not have a stringent delay constraint. In other words, the destination can potentially wait for a long period of time to decode the information from the source.
Most works have considered the non-fading case where nodes have knowledge about all channel conditions. The compress-forward relay and low-density parity-check (LDPC) code design has been considered for Gaussian channels. For the few works that consider the fading case, only the so-called decode-forward scheme has been considered, where the relay attempts to decode the source message before forwarding it to the destination. The rateless code with a precoder, i.e., Raptor code, has been studied for a general 2-node link channel without relaying.
Accordingly, there is a need for a transmission relaying protocol and practical coding for a quasi-static fading environment, which provides significant gains over the traditional point to point communication from the source to the destination.